Coating for Polymeric Labels

ABSTRACT

A coated thermoplastic film is disclosed. The film includes a polymeric substrate and a first coating layer. The polymeric substrate includes a first skin layer. The first coating layer on the first side of the first skin layer includes at least a first filler component. The filler component has a particular particle size relative to the open-cell, closed-cell or uncavitated structure of the first skin layer. Films and labels having improved balance of properties are described.

CROSS-REFERENCE TO RELATED APPLICATIONS

The application claims priority from U.S. Provisional Application Ser.No. 61/382,656, filed Sep. 14, 2010 and U.S. Provisional ApplicationSer. No. 61/323,219, filed Apr. 12, 2010, the contents of which areincorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

Polymeric labels are applied to a variety of bottles, containers andother surfaces to provide, for example, information about the productbeing sold or to display a trade name or logo. Polymeric labels canprovide various advantageous characteristics not provided by paperlabels, such as durability, strength, water resistance, curl resistance,abrasion resistance, gloss, translucence, and others.

The application of cut paper labels to glass and plastic containersusing water-based adhesives is still one of the most prevalent labelingtechniques. Consequently, there are many existing machines that havebeen installed for this type of labeling. These cut-label/patch-labellabeling techniques using water-based adhesives work well withpaper-based labels applied to glass, plastic, or metal substrates,because the wet adhesive wicks into and through the paper label. Thisrelease of the adhesive moisture through the labels allows the adhesiveto dry fully. This technique does not work, however, on polymeric labelsbecause the polymeric label does not permit wicking of the moisture fromthe adhesive when used as a decal on a window or a patch-label on acontainer. This can make the polymeric labels adhered with cold-gluetype adhesives prone to “swimming” or moving from the desired labellocation during downstream processing.

Polymeric label substrates having micro perforations to enhance the rateat which water trapped between the label and the substrate can evaporatehave had little success. Initial wet tack with commercially availablewater-based adhesives remained inadequate. Moreover, the microperforations tend to permit the passage of wet glue through the poresrendering the printed side of label on the container sticky and marringthe graphics.

It is known in the art to construct a multilayer film having a coatinglayer on the wet-adhesive-receiving surface of the film that includes afiller component. These films can offer fair performance as labels whenattached to containers with aqueous-based cold glues. However, thesefilms are known to have manufacturing and processing issues.

US2006/0046005, for example, discloses a polymer film coating for usewith cold glue labels, particularly on the adhesive-receiving side of alabel film. The coating is resistant to both water and solvent, andincludes a filler component and a binder component, at least one ofwhich is hydrophobic. This publication discloses that the fillers havingan average particle size ranging from 0.05 μm to 2000 μm may be used.Large particles, e.g., those with a diameter of 10 μm to 200 μm, aredescribed as attenuating surface roughness. Small particles, e.g., thosewith a particle size of <1.0 μm are described but their function is notdiscussed. Particles having a diameter of 1 μm to 8 μm are described asuseful as anti-abrasives to improve wet-scratch resistance, but suchparticles are described as serving no purpose in the adhesive sidecoating, rather they are used only for convenience in a symmetric filmstructure to facilitate production. US2006/0046005 also describesadhesive side skin layers that may be “open-cell voided,” “closed-cellvoided,” or uncavitated layers.

SUMMARY OF THE INVENTION

It has been discovered that where the size of the filler is carefullycontrolled, in combination with the selection of the adhesive-side skinlayer, the films may retain their suitability for cut and stackprocesses with reduced ink-transfer problems (i.e., ghosting effects)and mitigate print face deformation storing the film in stacking or rollform when the particle size is too large. Thus, contrary toUS2006/0046005, the particle size of the filler used in the adhesiveface, when coupled with the selection of the proper skin layerstructure, serves an important function. Thus, embodiments of thepresent invention provide improved film and label structures that aresuitable for cut and stack as well as roll-fed processes.

Embodiments of the invention provide coated thermoplastic filmscomprising: (a) a substrate comprising: (i) a first skin layer having anopen-cell voided structure, a closed-cell voided structure or anuncavitated structure, comprising a polymer, wherein the first skinlayer has a first side and a second side, (ii) an uncavitated core layercomprising a polymer, wherein the core layer has a first side and asecond side, and the first side of the core layer is adjacent to thesecond side of the first skin layer; and (b) a first coating on thefirst side of the first skin layer, the first coating comprising atleast a first filler component, the first filler component comprisingparticles having an effective diameter of 5.0 μm to 20.0 μm.

Particular embodiments relate to coated films, wherein the first skinlayer has an open-cell voided structure, and the first filler componentcomprises particles having a mean particle diameter satisfying thefollowing equation:

D _(mean) =N−T _(skin)

wherein

-   D_(mean) is the mean particle diameter (μm) of the first filler    component;-   T_(skin) is the thickness (μm) of the first skin layer; and-   N is in the range of 10.0 μm to 20.0 μm.

Some embodiments relate to coated films wherein the first skin layer hasa closed-cell voided structure or an uncavitated structure, and thefirst filler component comprises particles having a mean diameter in therange of 5.0 μm to 20.0 μm.

In another yet aspect, embodiments of the invention provide a coatedlabel film for use with a cold glue adhesive, the label film comprising:

-   -   (a) a substrate comprising:        -   (i) a first skin layer comprising a polymer, wherein the            first skin layer has a first side and a second side and is            voided with a closed-cell structure;        -   (ii) a core layer comprising a polymer, wherein the core            layer has a first side and a second side, and the first side            of the second core layer is adjacent to the second side of            the first skin layer;    -   (b) a first coating on the first side of the first skin layer        comprising at least a first filler component the filler        component comprising polyethylene homopolymer or copolymer        particles having a mean diameter in the range of 5 μm to 20 μm        and <2.0 number % of the filler particles have a diameter >75.0        μm.

In still another aspect, embodiments of the invention provide a coatedthermoplastic film comprising:

-   -   (a) a substrate comprising:        -   (i) a first skin layer having a closed-cell voided or            uncavitated structure, comprising a polymer, wherein the            first skin layer has a first side and a second side;        -   (ii) a uncavitated core layer comprising a polymer, wherein            the core layer has a first side and a second side, and the            first side of the core layer is adjacent to the second side            of the first skin layer;        -   (iii) second skin layer having a first side and a second            side, wherein the first side is adjacent the second side of            the core layer;    -   (b) a first coating on the first side of the first skin layer,        the first coating comprising a polyethylene filler component,        the polyethylene filler component comprising particles having a        mean diameter in the range of 5 μm to 20 μm, a second filler        component comprising 30 wt % to 60 wt % of a second filler        having particle mean diameter of ≦1.0 micron and a        self-cross-linking cationic acrylic first binder component; and    -   (c) a second coating on the second side of the second skin        layer, the second coating comprising a self-crosslinking        cationic acrylic composition.

The term coating can refer to a coating that is resistant to degradationfrom both water and solvent (e.g., a “resistant coating” or a “water-and solvent-resistant coating”). Particularly useful coatings describedherein are both water resistant and solvent resistant.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention provide coated thermoplastic filmscomprising: (a) a substrate comprising: (i) a first skin layer having anopen-cell voided structure, a closed-cell voided structure or anuncavitated structure, comprising a polymer, wherein the first skinlayer has a first side and a second side, (ii) an uncavitated core layercomprising a polymer, wherein the core layer has a first side and asecond side, and the first side of the core layer is adjacent to thesecond side of the first skin layer; and (b) a first coating on thefirst side of the first skin layer, the first coating comprising atleast a first filler component, the first filler component comprisingparticles having an effective diameter of 5.0 μm to 20.0 μm.

The term “mean diameter” is defined broadly to encompass substantiallythe mean based on the number of particles in a sample of any lineardistance across or through a particle having a relatively low aspectratio, or distance across the long-axis of particles having a highaspect ratio, such as a plate-like particle, or the nominal distancethrough a nominally spherical particle, as the filler particles maycomprise substantially any shape. When applied over the inherently roughfirst/adhesive-receiving side of the first skin layer, filler materialsprovide enough effective porosity to allow moisture permeation andmechanical penetration of the water component of the wet glue and/or ofthe wet glue itself, through the coating layer to the voided sub-layeradjacent to the coating. Insufficient particulate loading or a coatinglayer that is too thick can diminish retained cold glue adhesion whenlabeled bottles are immersed in ice water. The mean particle diametermay be determined by any suitable method, particularly by opticalmicroscopic evaluation of the particles of a particular type (i.e.,chemically distinguishable species), preferably based on a populationsize of at least 100 particles or according to ASTM D422. Where allparticles in the first skin layer are of the same type (i.e., they arechemically indistinguishable), determination of the mean particlediameter of the first filler component considers only particles havingan actual dimension (e.g., diameter) greater than 1.0 μm.

As used herein the term “effective diameter” refers to the mean diameterof the first filler particles described herein minus the portion of theparticle diameter that is effectively reduced due to the particlefalling, either partially or completely, into pores in the skin layerand/or compressed in the immediate vicinity of the particle by forcescaused by winding the coated film into a roll or stacking sheets of thecoated film. One skilled in the art can determine the effective diameterfrom the mean particle diameter, the mean pore size, and the skin layerthickness. Cavitated skin layers with open- or closed-cell voiding wouldboth be susceptible to compression, but generally, compressive effectsare relatively small and may be ignored for the purposes of determiningthe effective diameter unless their consideration changes the effectivediameter by >10%.

As used herein, the term “voided” is synonymous with the term“cavitated” as those terms are commonly understood within the art,referring to the creation of cavities, pores, or voids within a polymerfilm during orientation, whether using a void initiating agent orparticle, such as calcium carbonate, or without a void initiating agent,such as orienting the beta-form of polypropylene to create voids.

The term “closed-cell” with respect to film structures means that thereis substantially little to no effective inter-pore interconnectivity orcommunication. The term “closed cell” may be considered to include somedegree of near-surface fluid permeation due to surface roughness,including the irregularities, voids, craters, pores, tortuosities, andcavities, formed superficially, that is, on or near the surface of alayer, such as the first side of the first layer, as may be caused bythe voiding agents, other particulate additives, and/or orientation.Thereby, in many films, essentially closed cell layers, such as a printside skin layer, may exhibit some small degree of surface absorption dueto these features and thus exhibit some degree of openness with respectto the cell type. Such surface features may provide small reservoirs forfluid absorption and adhesive anchoring, even though inter-poreinterconnectivity with voids deeper within the first layer may belimited or substantially non-existent. Thereby, those skilled in the artwill recognize that film layers having a closed-cell structure may becapable of providing some degree of adhesive moisture absorption ortransmission.

The term “hydrophilic,” as used herein, means to be readily wettable bywater, having relatively low advancing contact angles with water, (e.g.,less than about)45° thereby being capable of binding or absorbing water.“Hydrophobic,” as used herein, is also defined to mean anything otherthan hydrophilic, including being water resistant or not being readilywater wettable.

The term “core layer” as used herein may refer to any inner layer of afilm substrate, where that layer is centrally located in a film or not.Core layers described herein may be monolayer or multilayer filmstructures. Core layers having any number of individual layers areenvisioned. A core layer may also comprise regions referred to as tielayers. Tie layers generally form the outer-most layers of the corelayer and can function to improve the interaction of the core layer withlayers such as skin layers or coatings.

The First Coating

Coating formulations according to this invention comprise at least afirst filler component and typically, although not necessarily, a bindercomponent. The coating formulation may also include a second fillercomponent and/or a polymer component. The coating can be applied by anymeans known in the art including, but not limited to, spraying, dipping,direct gravure, reverse direct gravure, air knife, rod, and offsetmethods, or combinations thereof.

First Filler

The first filler is selected to have an effective diameter of 5.0 μm to20.0 μm. As described above, the effective diameter depends on the meanparticle diameter, the mean pore size and the thickness of the firstskin layer. In some embodiments, particles having an effective diameterin the desired range are provided where the first filler componentcomprises particles having a mean diameter in the range of 5.0 μm to20.0 μm. In some embodiments, the first filler particles have a meandiameter in the range of 5.0 μm to 20.0 μm and <2.0 number % of thefiller particles have a diameter >75.0 μm. In some embodiments, suchfirst filler components comprise polyethylene homopolymer or copolymer,particularly surface treated polyethylenes. Some embodiments include asecond filler component comprising 30 wt % to 60 wt % of a second fillerhaving particle mean diameter of ≦1.0 micron.

Typically, the concept of matching the skin layer thickness to theparticle size is achieved using particles having a mean diameter in therange of from 5.0 μm to 20.0 μm. The lower end of the range of meanparticle size may be any value within the range of 5.0 μm to 20.0 μm,particularly 5.0 μm, 6.0 μm, 7.0 μm, 8.0 μm, 8.5 μm, 9.0 μm, 9.5 μm,10.0 μm, 10.5 μm, 11.0 μm, 11.5 μm, or 12.0 μm. Similarly, the upperlimit of the range of mean particle size may be any value within therange of 5.0 μm to 20.0 μm, particularly 10.0 μm, 10.5 μm, 11.0 μm, 11.5μm, 12.0 μm, 13.0 μm, 14.0 μm, 15.0 μm, 15.5 μm 16.0 μm, 16.5 μm, 17.0μm, 17.5 μm, 18.0 μm, 18.5 μm, 19.0 μm, 19.5 μm, or 20.0 μm. Exemplaryranges of mean particles size are 5.0 μm to 18.0 μm, 8.0 μm to 15.0 μm,or 10.0 μm to 15.0 μm.

Suitable fillers comprise clay materials, natural minerals,surface-treated natural minerals, synthetic minerals, surface-treatedsynthetic minerals, plastic or thermoplastic pigments or particulates,similar materials, and mixtures thereof.

In particular embodiments, the first filler component has a particularrelative amount of particles with in a certain size range. In someembodiments, <2.0 number % of the filler particles have a diameter >75.0μm, particularly >50.0 μm, more particularly >45.0 μm. In exemplaryembodiments, the coating includes a filler having a mean particledimension in the range of 10 μm to 15 μm wherein <2.0 number % of thefiller particles have a diameter >45.0 μm. In other embodiments, thecoating includes a filler having a mean particle dimension in the rangeof 15 μm to 20 μm wherein <2.0 number % of the filler particles have adiameter >65.0 μm. In some embodiments, at least 55.0 to 80.0 number %of the particles have a mean particle diameter in the ranges describedin the preceding paragraph. The lower limit on the number % of particlesin this range may be 55.0, 60.0, 65.0, 70.0, or 75.0. The upper limit onthe range of number % of particles in these ranges may be 78.0, 75.0,70.0, 65.0, 60.0, or 55.0.

It has been found that such filler components maintain advantage ofreduced ghosting (a phenomenon where ink on the print face transfers tothe adhesive face when the film is in roll and/or stack form) and remainsuitable for cut and stack processes, while also providing reduced printface deformation observed when larger particles are used.

Filler materials may be classified into two functional groups:hydrophilic and hydrophobic. Hydrophilic or hydrophobic particles willeach provide sufficient interstitial porosity to the coating to allowpenetration that enables good retained adhesion in an ice chest, astaught herein, provided there is sufficient filler particle loading.Hydrophilic fillers may include silicas, hydrophilic clays, bariumsulfate, calcium carbonate, titanium dioxide, zinc oxide, tin oxide,aluminum oxide, talc, carbon black, a wide variety of organic andinorganic pigments that could be used to make coated films with aspecific color, and mixtures of any two or more of the foregoing, havinghydrophilic properties. With hydrophilic fillers, internal particulatepore volume or porosity can influence the ability of given fillers toabsorb water. Hydrophilic filler materials may preferably have lowporosity or are effectively non-porous. In the context of the presentinvention, hydrophilic filler particles with low porosity means porosityof less than 3 milliliters/gram (ml/g) of water uptake per gram offiller material, with less than 1.5 ml/g being preferred, and less than0.5 ml/g being more preferred. Low-porosity and non-porous hydrophilicfillers have been found to provide better properties than their moreporous counterparts.

In addition to those listed previously, hydrophobic fillers commonlyinclude, but are not limited to, surface-modified clays,surface-modified silicas, and surface-modified titanium dioxide, whichhave been rendered water-resistant due to their surface modificationwith organic moieties. Examples of surface-modified clays includekaolinite clays sold under the trade name Kalophile-2™ by Dry BranchKaolin Company and Lithosperse® 7015 HS and 7005 CS by Huber EngineeredMinerals. An example of surface-modified silica is Aerosil™ RX50manufactured by Aerosil Nippon, in Japan. In accordance with the presentinvention, hydrophobic fillers are preferred, because it has been found,as demonstrated herein, that they offer better post-print blockingresistance during die-cutting and, when used on the print surface, thesematerials offer better wet-scratch resistance.

In particular embodiments, the filler component comprises polyolefinparticles. Particular polyolefins include polyethylene which as usedherein refers to a polyolefin homopolymer or copolymer containingrecurring units derived from ethylene. Such polyethylenes include butare not limited to polyethylene homopolymer and/or copolymer wherein atleast 85% (by number) of the recurring units are derived from ethylene.The polyethylene can be a mixture or reactor blend of individualpolyethylenes, such as a mixture of two or more polyethylenes.Particular embodiments include a polyethylene wax in the form orparticles having a mean diameter of from 5.0 μm to 20 μm, particularly5.0 μm to 18.0 μm, more particularly 8.0 μm to 15.0 μm. In particularembodiments, such polyethylene waxes have a weight average molecularweight in the range of 2,000 to 15,000 g/mol, particularly in the rangeof about 5,000 to about 10,000 g/mol. Polyethylene waxes may also haveone or more of the following features 1) Mw/Mn of from about 2 to 10, aviscosity number of from 10 to 60 cm³/g, a melting range of from about129° C. to 131° C. for a homopolymer and about 120° C. to 126° C. for acopolymer, and a density of from 0.930 to 0.970 g/cm³. One suitablepolyethylene is an oxidized HDPE, available as Acumist™ A12 or A18 fromHoneywell Specialty Additives.

Typically, coating compositions according to embodiments of theinvention include a first filler component in an amount less than 25.0wt % of the first coating, based on the total weight of the firstcoating. In some embodiments, the first filler component comprises lessthan 15.0 wt %, e.g., 5.0 wt % to 10.0 wt %, of the first coating, basedon the total weight of the first coating.

Binder

As described in more detail below, solvent resistance is typicallyimparted by the binder components, such as binders that are crosslinkedusing a crosslinker or which self-adhere, such as through polar bondingor self-crosslinking Other coating formulations according to embodimentsof the invention comprise a hydrophobic binder, as described herein, incombination with a hydrophilic filler, with the binder thereby impartinga predominant portion of the water resistance and solvent resistance,while the filler imparts moisture transmission through the coating.Thus, in many embodiments, the binder component is resistant to bothwater and solvents. However, in embodiments where the filler issubstantially hydrophobic, the binder material need not be ashydrophobic in nature and in some embodiments may permissibly containsome hydrophilic components or may be substantially hydrophilic butcomprise a crosslinker to improve solvent resistance.

Optional Second Filler

In some embodiments, the coating also comprises at least 30 wt %, orpreferably at least 45 wt %, and more preferably at least 60 wt % ofpreferably sub-micron size (meaning a particle mean diameter of equal toor less than about 1.0 micron) inorganic or organic filler materials.Suitable fillers comprise clay materials, natural minerals,surface-treated natural minerals, synthetic minerals, surface-treatedsynthetic minerals, plastic or thermoplastic pigments or particulates,similar materials, and mixtures thereof. In particular embodiments, thefirst coating includes a first binder component and a second fillercomponent. In some embodiments, a least one of the second fillercomponent and the first binder component is substantially hydrophobic.

Polymer Component

Some coating formulations also preferably comprise at least one polymer.Suitable polymers include, but are not limited to, acrylics, urethanes,hardened epoxies, alkyds, polystyrene copolymers, poly(vinylidenechloride)copolymers, butadiene copolymers, vinyl ester copolymers,nitrocellulose, and olefin copolymers, cross-linked, if necessary, torender them resistant to water and polar ink solvents (alcohols, esters,and ketones).

Optional Coating Additives

Many embodiments of the coating composition comprise a combination ofhydrophobic polymer binders, and optionally including minor amounts ofother additives, such as another polymer compound, organic or inorganicparticles, silica gel, pH modifiers, and buffering agents. The coatingformulations for adhesive-receiving layers (and, optionally, theprint-face coating) can also contain a wide variety of additivesincluding, but not limited to, wax emulsions, adhesion promoters,emulsifiers, anti-foams, defoamers, anti-static additives, securitytaggants, co-solvents, surfactants, and other wetting or processing aidsknown to those skilled in the art.

Substrate

Polymeric substrates referred to herein generally include a first skinlayer (having a first and second side) having a closed-cell voided oruncavitated structure and an uncavitated core layer comprising apolymer, wherein the core layer has a first side and a second side, andthe first side of the core layer is adjacent to the second side of thefirst skin layer. The first skin layer generally forms the substratesurface that is adjacent the article when the substrate is used as alabel or opposite a side of the substrate that is adjacent a productwhen the substrate is used as a packaging substrate. This surface of thesubstrate may typically be referred to as the back-side, e.g., anadhesive-receiving side, of the substrate and is typically the side ofthe substrate that is adjacent the article, product, or the side of thesubstrate that receives the labeling adhesive when the substrate is usedto form a label. The second surface of the substrate is generallyreferred to as, e.g., a top-side, front-side, or print-side of thesubstrate and is the side that is typically opposite theadhesive-receiving side of the substrate. In embodiments including asecond skin layer, the second skin layer forms the print-side of thesubstrate.

The term “polymeric substrate” or “substrate” as used herein may bedefined broadly to include any polymer or thermoplastic materialcomprising one or more monomers as a component thereof, preferablyoriented polymeric film structures. The polymeric substrate may bemonolayer or multilayer films, including oriented, coextruded, andlaminated multilayer films, and may preferably be biaxially orientedfilms. The polymeric substrate may also comprise other non-thermoplasticor non-polymeric materials, such as paper, cardstock, and/or metallic ornonmetallic substrates, and/or they may be laminated to suchnon-thermoplastic materials, such as paper, metallic, or non-metallicsubstrates. The polymeric substrate includes the polymeric portion plusany non-thermoplastic components that make up the structural compositionof the substrate. The polymeric substrate may include any clear, matte,cavitated, or opaque film. Many preferred embodiments may comprise anopaque or white film with substantially non-matte surfaces.

In some embodiments, the preferred polymeric substrate is a polyolefinfilm and more preferably a biaxially oriented, multi-layer or monolayerpolyolefin-based film comprising polypropylene, polyethylene, and/orpolybutylene homo-, co-, or ter-polymers. Other thermoplastic substratesor layers may also be present within such film embodiments, such aspolyesters. However, in other embodiments, the polymeric substrate caninclude substantially any thermoplastic material that forms a thin filmthat can be employed for packaging, labeling, or decoration. Otherexemplary suitable materials may include nylon, polyethyleneterephthalate, polylactic acid, and polycarbonate. The contemplatedsubstrates also include coextrudates of the foregoing materials,laminates of any two or more of these materials or interblends of any ofthe materials extruded as a single base film. Polyolefin homopolymersand copolymers of propylene and ethylene may be most useful in manylabeling applications. One particularly preferred polymeric substratethat is suitable as a facestock for labeling is a polypropylene-basedfilm containing at least 80 wt % of isotactic polypropylene in at leasta primary or core layer. Exemplary commercially available materialsinclude Exxon 4252 and FINA 3371.

The polymeric substrate may be coextruded with at least one skin layeror it may be laminated to at least one other film. Typically, when thefilm is coextruded the thickness of a skin layer may range from about 2%to about 18% of the total film thickness. Multilayer films having threeor more layers, e.g., five layers and sometimes even seven layers arecontemplated. Five-layer films may include a core layer, two skinlayers, and an intermediate layer between the core layer and each skinlayer, such as disclosed in U.S. Pat. Nos. 5,209,854 and 5,397,635. Theskin layers may include a copolymer (i.e., a polymer comprising two ormore different monomers) of propylene and another olefin such asethylene and/or 1-butene.

Another exemplary preferred substrate is a multilayer polypropylene filmcomprising at least one of polyethylene, polypropylene, copolymer ofpropylene and ethylene, copolymer of ethylene and 1-butene, terpolymersof any of the foregoing and maleic anhydride modified polymers. Anotheruseful substrate comprises polypropylene interblended with a minorproportion of at least one of polyethylene, copolymers of ethylene andan alpha olefin, copolymers of propylene and an alpha olefin,terpolymers of olefins and maleic anhydride modified polymers.Multilayer, white opaque, cavitated polypropylene-based films may alsobe a useful substrate. Such films are described in U.S. Pat. Nos.4,758,462; 4,965,123; and 5,209,884.

The polymeric substrate may also be treated and/or metallized on atleast one side. Many preferred polypropylene polymer-film embodimentsmay be treated on both sides to improve adherence of the print-sidecoating and the adhesive to the adhesive-receiving surface. Treatmentmay typically comprise corona, plasma, or flame treatment. In someembodiments, treatment may also comprise applying a primer to a surfaceof the polymeric substrate to improve adhesion between the substrate andthe back-side coating and/or the polymeric surface layer. Suchtreatments may facilitate uniform wetting of the coatings and/orincrease surface energy to improve coating anchorage to the substrate.The surface treatment typically may be applied after orientation,“in-line” on the coating equipment, though primers may typically beapplied using coating equipment. Some embodiments may possess skinlayers that do not require surface treatment for acceptable coating,ink, or adhesive adherence, such as layers comprising copolymers ofethylene and/or homopolymers of polyethylene, e.g., medium or highdensity polyethylene. Metallization may be by vacuum deposition ofaluminum or other metals. A print-face coating and printing ink may alsobe applied to the metallized or treated surface.

The polymeric substrates may be uniaxially oriented, or simultaneouslyor sequentially biaxially oriented. A typical range of orientationstretches the film 4 to 10 times its original dimension in the machinedirection and 7 to 12 times its original dimension in the transversedirection. The thickness of oriented polymeric substrates is notcritical and typically ranges from about 10 μm to about 100 μm.

First Skin Layer

The first skin layer comprises a polymer. In one embodiment, thethermoplastic polymer of the first skin layer, that is, the layerintended for contact with the coating and/or the adhesive, comprises atleast one polyolefin, including homo-, co-polymers (includingterpolymers and higher combinations of monomers, as used herein) ofpolypropylene and/or polyethylene. Examples of suitable polypropylenesinclude a standard film-grade isotactic polypropylene and/or a highlycrystalline polypropylene. An example of a suitable polyethylene ishigh-density polyethylene. In another embodiment, the first skin layercomprises copolymers of polypropylene including comonomers of C₂ or C₄to C₁₀ in an amount less than 50 wt % of the copolymer, and blends ofsaid polypropylene homopolymers and polypropylene copolymers.Particularly, the first skin layer comprises one or more polypropyleneor polyethylene homopolymers or copolymers and has a density of 0.500g/cm³ to 0.946 g/cm³.

In embodiments, the first skin layer is uncavitated. In otherembodiments, the first skin layer includes a first voiding agent tocavitate the layer during orientation. Examples of suitable cavitatingagents for essentially any voided or cavitated layer includespolyamides, polybutylene terephthalate, polyesters, acetals, acrylicresins, nylons, solid preformed glass particles or spheres, hollowpreformed glass particles or spheres, metal particles or spheres,ceramic particles, calcium carbonate particles, cyclic olefin polymersor copolymers (collectively, “COC's”), silicon dioxide, aluminumsilicate and magnesium silicate and mixtures thereof. COC's aredescribed in U.S. Pat. No. 6,048,608 issued to Peet et al., which isincorporated herein by reference in its entirety. The term “voidingagents” includes cavitating agents, foaming agents or blowing agents, ofsubstantially any shape. Suitable voiding agents (i.e., cavitatingagents) and voided skin layers (i.e., cavitated skin layers) aredescribed in U.S. application Ser. No. 09/770,960, which is incorporatedherein by reference.

In one embodiment, the first voiding agent makes up from about at least15.0 wt % to about at least 60.0 wt % of the first skin layer, and morepreferably, from about at least 25.0 wt % to about at least 50.0 wt % ofthe first skin layer and the first voiding agent may have a medianparticle diameter/size of from about 1.0 μm to about 5.0 μm and morepreferably from about 1.0 μm to about 3.0 μm. In another embodiment, thefirst voiding agent comprises at least about 20.0 wt %, at least about25.0 wt %, at least about 35.0 wt %, at least about 40.0 wt %, or atleast about 50.0 wt % of the first skin layer and the median particlesize of the voiding agent is in the range of 1.0 μm to 5.0 μm,preferably 1.0 μm to 3.0 μm. For example, in one embodiment, the medianparticle size of the voiding agent is at least about 1.4 μm. In anotherembodiment, the median particle size of the voiding agent is at leastabout 3.2 μm.

In many embodiments, the voiding agent employed in either the first skinlayer or the core layer is calcium carbonate having a particle sizerange in the range of 1.0 μm to 5.0 μm, preferably 1.0 μm to 2.0 μm andis preferably present in an amount of about 20.0 wt % to about 60.0 wt%, particularly in the skin layer. For example, in various embodiments,the quantity of 1.0- to 2.0-micron calcium carbonate is at least 25.0 wt%, or at least 35.0 wt %, or at least 40.0 wt % of the first skin layer.For some embodiments, the upper quantity limit of the 1.0- to 2.0-microncalcium carbonate is, for example, 60.0 wt % or less, of the respectivecavitated layer, while in other embodiments, the upper limit is no morethan about 50.0 wt % of the respective cavitated layer. All percentagesof calcium carbonate referred to herein are by weight, based on thetotal weight of the voided layer including the calcium carbonatetherein.

This first skin layer may be voided with a suitable first voiding agentto create voids or cells to provide a desired level of porosity and/orpermeability to aid absorption and/or dissipation of moisture fromaqueous adhesives, among other considerations related to voided films,such as yield, stiffness and opacity.

The first skin layer may have a particular surface roughness. Whenmeasured with an M2 Perthometer equipped with a 150 stylus from MahrCorporation, the average surface roughness (R_(a), output as defined inthe operating manual of the Perthometer) of the first skin layer istypically greater than 0.5 μm. R_(Z) (output as defined in the operatingmanual of the Perthometer), which weighs larger peaks more heavily, istypically greater than 4 μm.

Core Layer

The core layer comprises a polyolefin and has a first side and a secondside. The first side of the core layer is adjacent to, though notnecessarily directly in contact with, the second side of the first skinlayer. Preferably, the core layer has a thickness of approximately 50 toapproximately 950 gauge units (13 μm to 240 μm); however, for bettereconomics, the more preferred thickness of the core layer is betweenabout 50 to about 350 gauge units (13 μm to 90 μm).

In one embodiment, the core layer comprises polypropylene. Preferably,the polypropylene of the core layer is either isotactic or highcrystalline polypropylene. In another embodiment, the core layercomprises polyethylene. Preferably, the polyethylene is high-densitypolyethylene. In another embodiment, the copolymer of the core layer isa mini-random copolymer having an ethylene content on the order of 1.0wt % or less and 99.0 wt % or more of the co-polymer component, such aspolypropylene. In many embodiments, the core layer is voided. In suchembodiments, the core layer includes a second voiding agent, which maybe the same or a different agent as the first voiding agent used invoiding the first skin layer. The core layer may be voided utilizing thevoiding agents listed above and in concentrations as listed above, withparticle size and concentrations determined by the properties desired toimpart to the core layer. In other embodiments, the core may not bevoided. In either embodiment, non-void-creating particulate additives orfillers, such as titanium dioxide, can be included in the core layer toenhance opacity.

In some embodiments, the core layer includes a first tie layer thatforms the first side of the core layer and is in surface contact withthe first skin layer. In some embodiments, the core layer includes aregion that may be called a second tie layer. The second tie layer formsthe second side/surface of the core layer. Where a second skin layer ispresent, the second tie layer is in surface contact with the second skinlayer. These tie layers may include homo-, co-, or terpolymerscomprising polypropylene, polyethylene, polybutylene, or blends thereofand may have a thickness of at least about 0.3 mil (0.75 μm). The firstside of the first tie layer is adjacent to the second side of the firstskin layer; and the first side of the core layer is adjacent to thesecond side of the first tie layer. The second side of the second tielayer is adjacent to the first side of the second skin layer; and thesecond side of the core layer is adjacent to the first side of thesecond tie layer.

In some embodiments, the core and/or tie layer(s) may also include aconventional non-void-inducing filler or pigment such as titaniumdioxide. Generally, from an economic viewpoint at least, it has not beenconsidered to be of any particular advantage to use more than about 10wt % of titanium dioxide to achieve a white label suitable for printing.Greater amounts could be added for greater opacity so long as there isno undue interference with achieving the desired properties of athermoplastic label.

Optional Second Skin Layer

Many preferred embodiments also possess a second skin layer on a side ofthe core layer opposite the first skin layer. The second skin layercomprises a polyolefin and has a first side and a second side. The firstside of the second skin layer is adjacent to the second side of the corelayer, though not necessarily directly in contact with the core layer.Preferably, the second skin layer is on the order of 10 to 25 gaugeunits (2.5 μm to 6.4 μm) in thickness. Suitable polyolefins for thesecond skin layer include polyethylene, polypropylene, polybutylene,polyolefin copolymers, and mixtures thereof. In many label embodiments,the second skin layer is not voided or when voided, is typically onlylightly voided and has a substantially closed-cell type void structure.The second/exterior side is suitable for a surface treatment such asflame, corona, and plasma treatment; metallization, coating, printing;and combinations thereof

In one embodiment, the second side of the second skin layer ismetallized or is a glossy surface that is capable of dissipating static.In another embodiment, the metallized or glossy surface is coated with apolymeric coating. In still another embodiment, the second side of thesecond skin layer is coated with a relatively rough, non-glossy materialthat is also capable of dissipating static. Such coating may be acoating having properties and components according to this invention.For example, the coating on the second side of the second skin layer maybe the same coating, as used on the first side of the first skin layer.Still other embodiments will employ a voiding agent in the second skinlayer and/or the core layer, wherein such voiding agent has a medianparticle size of 1.5 μm or less, such that when the second skin layer ismetallized, a bright mirrored appearance will result. The second skinlayer is preferably treated to improve surface adhesion, such as bycorona treatment. In an exemplary embodiment of this invention, the skinlayer intended to receive the metallized coating has a thickness ofapproximately 20 gauge units (5 μm) or less.

Films described in US Patent Application Publication Nos. 2002/0146520and 2003/0172559, and U.S. Pat. No. 7,288,304, incorporated herein byreference in their entireties, disclose representative compositionssuitable as the optional second layer.

Optional Second Coating Layer

Embodiments of the invention include films having a coating on theprint-side of the film. The coating may be applied to the core layer orthe optional second skin layer, when present. The coating may be appliedby any means known in the art, such as direct gravure, reverse-directgravure, offset, spraying, or dipping. The optional second coating mayalso may be applied to a metallized, matte or glossy print-side surfaceto protect such side and/or to dissipate static charge therefrom.Although anti-static protection may be applied to either side of a filmsubstrate, typically it is not necessary to provide anti-staticprotection to both sides of the film structure. For example, the surfaceresistivity of the print surface may be less than 14 log ohms per square(per square geometric region as measured on a circular film sampleinserted into a Keithley Model 8008 Resistivity Test Fixture with 500volts applied using a Keithley Model 487 Picoammeter/Voltage Source, oralternatively using an Autoranging Resistance Indicator Model 880 fromElectro-Tech Systems, Inc., Glenside, Pa.), when the relative humidityis greater than 50% and the metallized surface is reflective or thegloss is >30% when measured with a BYK Gardner Micro-gloss 20° meter.Adequate gloss and metallic sheen can be obtained from using a base filmwhich is uniaxially or biaxially oriented and which has a second/printside that contains only substantially closed-cell voids, a relativelylow percentage of voids, or no voids at all on the gloss or metallicsecond/print side. In the metallized embodiments, metal, such asaluminum, is deposited on the smooth, print side.

Formulations described for the first coating may also be used for theoptional second coating.

Optional second coatings also include smooth, clear polymeric coatingsapplied over the core layer, the optional second skin layer, or themetallic layer deposited on thereon Such polymeric coating can beapplied by any means known in the art including, but not limited to,application of polymeric material dispersed in water or dispersed in asolvent, and extrusion coating. Such coatings may further enhance glossor preserve a desired metallic appearance of a metallized film.

The outer print/metallization surface of the film preferably has anaverage roughness (R_(a)) of between 0.1 μm and 0.3 μm, preferably lessthan 0.3 μm, more preferably less than 0.15 μm, before metallization.(R_(a) can be measured with an M2 Perthometer from Mahr Corporationequipped with a 150 stylus.) In some embodiments, the second skin layeris coated with a relatively rough, non-glossy material that is capableof dissipating static. That is, the surface resistivity is less than 14log ohms/square when the relative humidity is greater than 50%, gloss is<30% when measured with a BYK Gardner Micro-gloss 20° meter. In someembodiments the surface-applied coating has a roughness R_(a) that isgreater than 0.20 μm and an R_(a) that is greater than 1.0 micron whenmeasured with a Perthometer S2 from Mahr Corporation, Cincinnati, Ohio,especially such a model equipped with a 150 stylus. For good printquality, the roughness R_(a) is preferably less than 0.35 and R_(Z) ispreferably less than 3.0 μm. When measured with a Messmer ParkerPrint-Surf Roughness and Air Permeability Tester Model ME-90, the roughcoating for the second side of the second skin layer preferably has anaverage roughness between 0.75 μm and 3 μm, more preferably between 1 μmand 2 μm. Suitable examples of relatively rough, non-glossy coatingshaving wet-scratch resistance are described in U.S. Pat. No. 6,025,059and U.S. Patent Application Publication No. 2003/0207121, whichdisclosures are incorporated herein by reference in their entireties.Another example is PD900 NT from Process Resources Corporationcross-linked with polyfunctional aziridine, such as CX-100 from Avecia,and NAC-116, an anti-static additive from Process Resources Corporation.

In embodiments wherein the second side of the second skin layer ismetallized, preferably, a coating is applied to the metallized surface.Such coatings may provide desirable print qualities includingwet-scratch resistance, machinability enhancement, and mar resistance.Suitable examples are described in U.S. Pat. Nos. 6,025,059 and6,893,722, which disclosures are incorporated herein by reference intheir entireties. Additionally, a variety of urethanes, acrylics,polyesters, and blends thereof may also be suitable. Suitable examplesare described in U.S. Pat. Nos. 5,380,587 and 5,382,473, whichdisclosures are incorporated herein by reference in their entireties.

Preferred printable coatings for the optional second coating may provideexcellent anchorage for inks, including radiation curable inks, such asultra-violet (“UV”) radiation cured inks, and many other types of inkssuch as discussed below. To provide a durable, scratch resistant, or marresistant print-surface on the film, many preferred embodiments arecoated with a cross-linked or cured coating. Preferred coatings may alsoresist attack by isopropyl alcohol (IPA) and hot water. Examples of suchcoatings are described by McGee in U.S. Pat. Nos. 6,596,379 and6,893,722; Touhsaent in U.S. Pat. No. 6,844,034; and Servante in U.S.Pat. No. 7,758,965. These patents and application are incorporatedherein, by reference, in their entirety. In many preferred pressuresensitive label embodiments, the coatings described by McGee in U.S.Pat. No. 6,893,722 may be especially preferred, as they may provide adurable, pasteurizable, printable surface. Other suitable front-sidecoatings may include acrylic-based coatings and other water-orsolvent-based printable coatings that are substantially clear when dry.

Preferably, water- and solvent-resistant coatings applied to themetallized surface do not significantly diminish the bright mirroredappearance of the metallized surface. Similar coatings can be used onthe second side of the second skin layer without metallizing. However,such structures would lose a significant contribution to the anti-staticproperties made by the metal and depending upon the formulation of theclear coating, anti-static additives may then be necessary in thecoating formulation for the print face.

In some embodiments, the surface resistivity of the second skin layerand the layer coated with the water- and solvent-resistant filledcoating is less than about 14 log ohms/square, more preferably less thanabout 12 log ohms/square, and most preferably less than about 10 logohms/square. Surface resistivity measurements may be made with anAutoranging Resistance Indicator Model 880 from Electro-Tech Systems,Inc., Glenside, Pa., especially when measuring a surface that ismetallized or that has a clear coating over the metal. However, thisdevice cannot measure resistances above 12 log ohms/square.Alternatively, surface resistivity may be measured using a 487Picoammeter/Voltage Source equipped with an 8008 Resistivity TestFixture supplied by Keithley Instruments, Cleveland, Ohio, especiallywhen the surface resistivity exceeded 12 log ohms/square. For themeasurements made with the Keithley meter, the instrument applies 500volts to the surface of the sample.

Film Structures

In one embodiment, the label film comprises three layers; that is, afirst skin layer on the adhesive-receiving side of the film, acore/interior layer (which may also include tie layers) and a secondskin layer on the side of the core layer opposite the first skin layer.The first skin layer has a first side and a second side and includes athermoplastic polymer. The first skin layer is either voided with aclosed-cell structure or uncavitated. In some embodiments, the firstside preferably is intended for receiving both a coating according tothis invention thereon, and subsequently, a cold-glue type adhesive or ahot-melt type adhesive on the coating. The first skin layer typicallyhas a thickness in the range of 15 to 25 gauge units (0.15 mil to 0.25mil, or 3.8 μm to 6.4 μm), but this is not critical. Thermoplastic filmsand labels according to such embodiments typically have an overallthickness, including both skin layers, the core layers and anyadditional layers, of from about 1 mil to about 10 mils (25 μm to 250μm), preferably from about 3 mils to about 5 mils (75 μm to 125 μm),with many embodiments comprising a three- to five-layer white opaquefilm. In some label film embodiments, the adhesive-receiving first skinlayer makes up at least about 15 wt % of the film label. In anotherembodiment, the first skin layer comprises at least about 30 wt % of thefilm label. Preferably, the thermoplastic films useful according to thisinvention, including the label films, are biaxially oriented. In anotherembodiment, the films are uniaxially oriented.

Additional Optional Additives

Other conventional additives, in conventional amounts, may be includedin the coatings or films of the invention. Suitable other conventionaladditives include anti-oxidants, pigments, orientation stress modifiers,flame-retardants, anti-static agents, anti-blocking agents, anti-fogagents, and slip agents. Another class of additives that may be includedin the film structures according to this invention is low molecularweight hydrocarbon resins (frequently referred to as “hard resins”). Theterm “low molecular weight hydrocarbon resins” refers to a group ofhydrogenated or unhydrogenated resins derived from olefin monomers, suchas the resins derived from terpene monomers, coal tar fractions, andpetroleum feedstock. Such suitable resins prepared from terpene monomers(e.g., limonene, alpha and beta pinene) are Piccolyte resins fromHercules Incorporated, Wilmington, Del., and Zonatac resins from ArizonaChemical Company, Panama City, Fla. Other low molecular weight resinsare prepared from hydrocarbon monomers, as C₅ monomers (e.g.,piperylene, cyclopentene, cyclopentadiene, and isoprene), and mixturesthereof. These are exemplified by the hydrogenated thermallyoligomerized cyclopentadiene and dicyclopentadiene resins sold under thetrade name Escorez (i.e., Escorez 5300) by ExxonMobil Chemical Companyof Baytown, Tex. Others are prepared from C₉ monomers, particularly themonomers derived from C₉ petroleum fractions which are mixtures ofaromatics, including styrene, methyl styrene, alpha methyl styrene,vinyl naphthalene, the indenes and methyl indenes and, additionally,pure aromatic monomers, including styrene, α-methyl-styrene, andvinyltoluene. Examples of these resins include hydrogenated a-methylstyrene-vinyl toluene resins sold under the trade name Regalrez byHercules Incorporated of Wilmington, Del.

Film Properties

Thermoplastic films and labels according to the present invention maytypically have an overall thickness, including the skin layer(s), thecore layers and any additional layers, of from about 1 mil to about 10mils (25 μm to 250 μm), preferably from about 3 mils to about 5 mils (75μm to 125 μm), with many embodiments comprising a three- to five-layerwhite opaque film. In some label film embodiments, theadhesive-receiving first skin layer makes up at least about 15 wt % ofthe film label. In another embodiment, the first skin layer comprises atleast about 30 wt % of the film label. Preferably, the thermoplasticfilms useful according to this invention, including the label films, arebiaxially oriented. In another embodiment, the films are uniaxiallyoriented.

In film substrate embodiments comprising a cavitated first skin layerand a core layer, and optionally including a first tie layer, thedensity of the film substrate, excluding any coatings, metallization,and printing inks, etc., is preferably within a range of at least about0.3 g/cc to about 0.8 g/cc. A lower bulk density may result in a film ofunsuitable matrix/structural integrity, unless laminated to a strongerlayer, and a higher bulk density may provide insufficient porosity forthe effective absorption of moisture from the cold glue adhesive. Thesebulk density limits may vary somewhat, in films with relatively thickcores or relatively thin skins. For example, a film having a heavilycavitated core and/or tie layer may be cavitated such that the bulkdensity is slightly lower than 0.3 g/cc, while a film comprising arelatively thin cavitated first skin layer with relatively thicknon-cavitated tie and core layers may exhibit a bulk density in excessof 0.8 g/cc. Thus, the term “about” is intended to incorporate such filmstructures that fall outside of the stated range but which are otherwiseutilized according to this invention.

Label Structures

Embodiments of the invention also include containers or substrateslabeled with the thermoplastic films described herein. Some such labelsprovide one or more advantages over currently used paper and polymericlabels. For example, some labels may include coatings on the print sideand/or the adhesive-receiving layer of paper labels to make some of theadvantages of the coating available to paper label applications. Inembodiments related to labels or labeled containers, an adhesive may beapplied to the first skin layer. Preferably, the adhesive is awater-based adhesive, e.g., cold glues as commonly used in container orbottle labeling operations. Water-based adhesives are well known in theart for use with traditional paper labels.

As referenced herein, adhesive is applied to the first side of the firstskin layer of the films of the present invention. Cold glue adhesivesgenerally comprise solid base materials in combination with water. Inone embodiment, the cold glue is an aqueous solution of a naturaladhesive (e.g., casein). In another embodiment, the cold glue is anaqueous solution of a resin (e.g., poly(vinyl acetate) (PVA) or ethylenevinyl acetate (EVA)). Cold glues are widely used as an economicalalternative to wrap around or pressure sensitive labels. Some cold gluesare a colloidal suspension of various proteinaceous materials in waterand are derived by boiling animal hides, tendons, or bones that are highin collagen. Alternatively, cold glue can be derived from vegetables(e.g., starch, dextrin). Some cold glues are based on syntheticmaterials (resins). Examples of cold glues which are suitable for thepractice of the present invention include HB Fuller WB 5020, NationalStarch Cycloflex 14-200A, AABBITT 712-150; Henkel Optal 10-7026; HenkelOptal 10-7300; and Henkel Optal 10-7302. Exemplary suitable hot-meltadhesives include North West Adhesives A48, Henkel 3963, Henkel 377, HBFuller 4165. The aforementioned list of cold glues contains trademarksof HB Fuller, National Starch, AABBITT, and Henkel, respectively.

The coated film labels comprising the water-based adhesive are attachedto containers by means known in the art. The containers have a surfacethat is adjacent to the glue applied to the coatedfirst/adhesive-receiving side of the first skin layer of the label.Suitable materials for the container include glass, ceramics,thermoplastics, metal and other materials. The present inventionprovides containers having a thermoplastic film label. These containersinclude a surface of the container; a water-based adhesive adjacent tothe container surface; and a hydrophobic-coated thermoplastic filmlabel. The coated thermoplastic film label is as described above.

Particular Embodiments

-   1. Embodiments of the invention provide a coated thermoplastic film    comprising:    -   (a) a substrate comprising:        -   (i) a first skin layer having an open-cell voided structure,            a closed-cell voided structure or an uncavitated structure,            comprising a polymer, wherein the first skin layer has a            first side and a second side;        -   (ii) an uncavitated core layer comprising a polymer, wherein            the core layer has a first side and a second side, and the            first side of the core layer is adjacent to the second side            of the first skin layer; and    -   (b) a first coating on the first side of the first skin layer,        the first coating comprising at least a first filler component,        the first filler component comprising particles having an        effective diameter of 5.0 μm to 20.0 μm. In particular        embodiments the first skin layer has an open-cell voided        structure, and the first filler component comprises particles        having a mean particle diameter satisfying the following        equation:

D _(mean) =N−T _(skin)

-   -   wherein    -   D_(mean) is the mean particle diameter (μm) of the first filler        component;    -   T_(skin) is the thickness (μm) of the first skin layer; and    -   N is in the range of 10.0 μm to 20.0 μm.

-   2. Embodiments of the invention include coated films according to    paragraph 1, wherein the first skin layer has a closed-cell voided    structure or an uncavitated structure, and the first filler    component comprises particles having a mean diameter in the range of    5.0 μm to 20.0 μm.

-   3. Embodiments of the invention include coated films according to    any of paragraphs 1 and 2, wherein the first filler component    comprises particles having a mean diameter in the range of 8 μm to    18 μm.

-   4. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 3, wherein the first filler    component comprises particles having a mean diameter in the range of    5 μm to 15 μm.

-   5. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 4, wherein the first coating    further includes a first binder component and a second filler    component.

-   6. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 4, wherein the first coating    further includes a first binder component and a second filler    component, and wherein a least one of the second filler component    and the first binder component is substantially hydrophobic.

-   7. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 6, wherein the first skin layer    comprises a polypropylene or polyethylene and has a density of 0.500    g/cm³ to 0.946 g/cm³.

-   8. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 7, wherein the substrate (a)    further comprises: a second skin layer comprising a polymer, wherein    the second skin layer has a first side and a second side, the first    side of the second skin layer is adjacent to the second side of the    first core layer, and the second side of the second skin layer is    suitable for a surface treatment selected from the group consisting    of flame, corona, plasma, metallization, prime coating, printing,    and combinations thereof

-   9. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 8, wherein the first filler    component comprises at least one of: a) a clay material; b) a    natural mineral material; c) a surface-treated natural mineral; d) a    synthetic mineral; e) a surface-treated synthetic mineral; f)    plastic particulates; and g) thermoplastic particulates.

-   10. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 9, wherein the first filler    component comprises at least one of: a) a surface-modified clay; b)    plastic particulates; and c) thermoplastic particulates.

-   11. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 10, wherein the first filler    component comprises a surface-treated polyolefin, e.g.,    surface-treated polyethylene.

-   12. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 11, wherein the first binder    component comprises at least one polymer of the group consisting of    acrylics, urethanes, hardened epoxies, alkyds, polystyrene    copolymers, poly(vinylidene chloride) copolymers, butadiene    copolymers, vinyl ester copolymers, nitrocellulose, and olefin    copolymers.

-   13. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 12, wherein the first coating    further comprises: at least one of organic particles, inorganic    particles, silica gel, anti-static material, wetting agents,    surfactants, security taggants, pH modifiers, and buffering agents.

-   14. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 13, wherein the first coating is    applied to the film at a weight of from about 0.1 g/m² to about 4.0    g/m², particularly from about 0.2 g/m² to about 2.5 g/m², more    particularly from about 0.8 g/m² to about 2.0 g/m².

-   15. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 6 and 8 to 14, wherein the    substrate (a) further comprises: a second skin layer comprising a    polymer, wherein the second skin layer has a first side and a second    side, the first side of the second skin layer is adjacent to the    second side of the first core layer, and the second side of the    second skin layer is suitable for a surface treatment selected from    the group consisting of flame, corona, plasma, metallization, prime    coating, printing, and combinations thereof, and a second coating    comprising at least a third filler component and a second binder    component, the second coating applied to the second side of the    second skin layer, wherein at least one of the third filler    component and the second binder component is substantially    hydrophobic.

-   16. Embodiments of the invention include coated films according to    paragraph 15, wherein the second coating is applied to the film at a    weight of from about 0.1 g/m² to about 4.0 g/m².

-   17. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 16, wherein the first filler    component comprises less than 25.0 wt %, particularly less than 15.0    wt %, more particularly 5.0 wt % to 10.0 wt % of the first coating,    based on the total weight of the first coating.

-   18. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 17, wherein the first binder is    substantially hydrophobic and the first filler material is    substantially hydrophilic, the first filler comprising at least one    of: a) silica; b) hydrophilic clays; c) barium sulfate; d) calcium    carbonate; e) titanium dioxide; f) zinc oxide; g) tin oxide; h)    aluminum oxide; i) talc; j) carbon black; and k) another pigment.

-   19. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 18, wherein the first binder    further comprises a crosslinker, particularly where the crosslinker    comprises at least one of zirconium salts of mineral acids,    polyfunctional aziridine, zinc salts, zirconium salts, glyoxal,    melamine-formaldehyde resins, polyfunctional isocyanates,    polyfunctional amino compounds, polyfunctional vinyl compounds, and    polyfunctional epoxy compounds.

-   20. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 19, wherein the first coating    further comprises at least one of wax emulsions, adhesion promoters,    emulsifiers, anti-foams, defoamers, anti-statics, security taggants,    co-solvents, wetting aids, and processing aids.

-   21. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 20, wherein the first skin layer    further comprises a voiding agent selected from the group consisting    of polyamides, polybutylene terephthalate, polyesters, acetals,    acrylic resins, solid preformed glass particles, hollow preformed    glass particles, metal particles, ceramic particles, calcium    carbonate, cyclic olefin polymers, cyclic olefin copolymers, silicon    dioxide, aluminum silicate, magnesium silicate, and mixtures    thereof.

-   22. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 21, wherein the first core layer    further comprises a voiding agent selected from the group consisting    of polyamides, polybutylene terephthalate, polyesters, acetals,    acrylic resins, solid preformed glass particles, hollow preformed    glass particles, metal particles, ceramic particles, calcium    carbonate, cyclic olefin polymers, cyclic olefin copolymers, silicon    dioxide, aluminum silicate, magnesium silicate, and mixtures thereof

-   23. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 22, wherein the polymeric    substrate without the first coating has a density of from about 0.30    g/cm³ to about 0.80 g/cm³.

-   24. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 23, wherein the first coating is    in the form of a continuous layer on the first side of the first    skin layer.

-   25. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 24, wherein the first coating is    in the form of a pattern or non-continuous layer on the first side    of the first skin layer.

-   26. Embodiments of the invention include coated films according to    any combination of paragraphs 1 to 25, wherein the first coating    layer further comprises a primer layer in surface contact with the    first side of the first skin layer.

-   27. Particular embodiments include coated label films for use with a    cold glue adhesive, the label film comprising:    -   (a) a substrate comprising:        -   (i) a first skin layer comprising a polymer, wherein the            first skin layer has a first side and a second side and is            voided with a closed-cell structure;        -   (ii) a core layer comprising a polymer, wherein the core            layer has a first side and a second side, and the first side            of the second core layer is adjacent to the second side of            the first skin layer; and    -   (b) a first coating on the first side of the first skin layer        comprising at least a first filler component the filler        component comprising polyethylene homopolymer or copolymer        particles having a mean diameter in the range of 5 μm to 20 μm        and <2.0 number % of the filler particles have a diameter >75.0        μm.

-   28. Particular embodiments also include coated thermoplastic films    comprising:    -   (a) a polymeric substrate comprising:        -   (i) a first skin layer having a closed-cell voided or            uncavitated structure, comprising a polymer, wherein the            first skin layer has a first side and a second side;        -   (ii) a uncavitated core layer comprising a polymer, wherein            the core layer has a first side and a second side, and the            first side of the core layer is adjacent to the second side            of the first skin layer;        -   iii) second skin layer having a first side and a second            side, wherein the first side is adjacent the second side of            the core layer;    -   (b) a first coating on the first side of the first skin layer,        the first coating comprising a polyethylene filler component,        the polyethylene filler component comprising particles having a        mean diameter in the range of 5 μm to 20 μm, a second filler        component comprising 30 wt % to 60 wt % of a second filler        having particle mean diameter of ≦1.0 micron and a        self-cross-linking cationic acrylic first binder component; and    -   (c) a second coating on the second side of the second skin        layer, the second coating comprising a self-crosslinking        cationic acrylic composition.

-   29. Embodiments of the invention include coated films according to    paragraph 28, wherein the core layer include a first tie layer    region and a second tie layer region, the first tie layer region    forming the first side of the core layer and the second tie layer    region forming the second side of the core layer.

This disclosure is merely illustrative and descriptive of the inventionby way of example and various changes can be made by adding, modifying,or eliminating details without departing from the fair scope of theteaching contained in the disclosure. It will be recognized by thoseskilled in the art that various changes to the embodiments or methodsherein as well as in the details may be made within the scope of theattached claims without departing from the spirit of the invention.However, such modifications and adaptations are within the spirit andscope of the present invention.

EXAMPLES Comparative Example 1

The underlying film in Comparative Example 1 onto which a coating isapplied is a biaxially oriented five-layer opaque film suitable forlabeling applications, e.g., 85BF or 160LL302 film available fromExxonMobil Chemical Films. Suitable base films, including 85BF and160LL302, have a structure shown below, wherein all percentages are byweight based on the total weight of the recited components of individuallayers. The relative amounts of the individual layers in the film isalso indicated, e.g., in certain embodiments Skin Layer 1 comprises 5.0wt % to 9.0 wt % of the base film.

Adhesive-Receiving Surface

Skin Layer 1 (5.0-9.0%) OPP or HCPP + 0.0-60.0% voiding agent +0.0-15.0% Antiblock Tie Layer 2 (5.0-30.0%) OPP or HCPP Core Layer 3(52.5-88.5%) OPP or HCPP + 0.0-15.0% voiding agent Tie Layer 4(0.0-30.0%) OPP or HCPP + 0.0-10.0% Antistat Skin Layer 5 (1.0-3.5%)Propylene-ethylene copolymer + 0.0-15.0% Antiblock

Print-Receiving Surface (with or sans Metal)

The term “OPP” means polypropylene resin, the term “HCPP” means highcrystallinity polypropylene resin. An adhesive surface coating isapplied to Skin Layer 1 of the 85 BF base film. The coating comprisesabout 2.3 g/m² of filled coating containing emulsion-based binders andfillers. One component of the filled coating comprises MD145 availablefrom Michelman, Inc., which comprises 175 dry parts (a parts are on adry basis) of a first filler component (micronized oxidized high-densitypolyethylene available as ACumist® A-45 from Honeywell) having a meandiameter of 30-40 μm and a largest particle diameter of 125 μm; 250 dryparts of a second filler component (sub-micron clay available asLithosperse 7005 CS from Huber, which is clay treated with an inorganicmaterial to render the clay hydrophobic) per 100 dry parts of R1117 XL(a cationic acrylic emulsion from Owensboro Specialty Polymer, LLC) asthe binder. Prior to coating, MD145 is blended with 68 dry parts epoxybinder described by Steiner et al. (U.S. Pat. No. 4,214,039) per 100 dryparts of R1117 XL. Thus, the completed coating contained about 72 wt %fillers (28% binders), not counting other minor formulation additives.The print face, i.e., Skin Layer 5 is corona treated and metallizedbefore being coated with a coating suitable for printing.

Example 1

Comparative Example 1 is substantially reproduced except that MD145 wasreplaced with MD118, also from Michelman, Inc. MD118 is similar to MD145except that the first filler component of Comparative Example 1 isreplaced with a filler comprising 36 phr (per 100 phr R1117XL)polyethylene particles (Acumist A18) having a mean particle diameter of18 μm (individual batches ranged from 16 μm to 19 μm) and a largestparticle diameter of 62 μm.

Example 2

Comparative Example 1 is substantially reproduced except that MD145 wasreplaced with MD112, also from Michelman, Inc. MD112 is similar to MD145except that the first filler component of Comparative Example 1 isreplaced with a filler comprising 36 phr (per 100 phr R1117XL)polyethylene particles (Acumist A12) having a mean particle diameter of12 μm (individual batches ranged from 10 μm to 13 μm) and a largestparticle diameter of 44 μm.

The resulting coated films are evaluated for suitability for both cutand stack and roll-fed processes. Example 1 and Example 2 demonstratethat the smaller first filler outperforms the control/ComparativeExample 1 with respect to print face embossing, sheeting performance,ghosting, and moisture absorption.

To evaluate the level of print face embossing, 28″×40″ sheets of filmare printed on a 6-color Mitsubishi Off-set printing press at a standardpress speed of 7,500 to 8,500 sheets per hour. The printed surface ofthe film is evaluated based on the density of the embossing defect.Experimental variables were qualitatively rated against the control on a1-to-5 scale with a score of 3 used for the control film. A score of a 1or 2 represents an increase in density of the defect seen on the printsurface, with 1 representing a higher density than 2. A score of a 4represents a decrease in the density of the defect. A score of a 5represents a removal of the embossing defect. Higher numbers aredesirable.

To test sheeting performance, film is run on a Valmet TSK TwinSynchronous Knife machine. Two parameters are used to evaluate theperformance of the film: 1) the speed of the machine; and 2) the amountof operator attention required to complete the sheeting operation isrecorded for each variable: Comparative Example 1 (control film, 45μparticle size variable film), and (Example 1 and Example 2) theexperimental variables, 18μ and 12μ particle size film. The controlfilm, 45μ particle size film, runs at 200 feet per minute and requiresconstant operator attention. The 18μ particle runs at 200-210 feet perminute without any operator attention. The 18μ particle film runs up to250 feet per minute with intermittent operator attention. The 12μparticle runs up to 250 feet per minute without any operator attention.The film is rated against the control on a 1-to-5 scale with a score of3 used for the control film. A score of 4 represents an improvement inone of the two parameters evaluated: machine speed or amount operatorattention required. A score of 5 represents an improvement in two of thetwo parameters evaluated.

Ghosting is the term used in the trade when, as the ink dries, anyamount of ink on the printed surface transfers to the backside of thefilm. Ghosting occurs after the film is printed with ink and the film isthen rewound or stacked on top of itself. No ghosting is desirable. Thefilm was evaluated for ghosting after printing on a 6-color MitsubishiOff-set printing press. Comparative Example 1 exhibited ink transfer.Example 1 and Example 2 exhibited no ink transfer.

Wettability/Surface Energy is measured via a contact angle meter (fromTantec AS). Contact angle is defined as the angle between the tangentline at the contact point and the horizontal line of the surface. Thechange in the contact angle (in degrees) of a droplet of DI H₂O onto theadhesive receiving surface of the coated film is measured over a 5minute test. This test is completed twice and the result reported is theaverage change in angle. The average range is from 0 to 22.5 degrees.Higher numbers are desirable. The following table shows the results:

TABLE 1 Summary of Testing Results Comparative Example 1 Example 1Example 2 45μ particle 18μ particle 12μ particle Print Face Embossing 35 5 Sheeting Performance 3 4 5 Ghosting Yes No No Wettability/Surface11.5 18.5 16.3 Energy (degrees)

Examination of the data in Table 1 reveals that Example 1 and Example 2preformed better than Comparative Example 1 in the areas of Print FaceEmbossing, Sheeting Performance, Ghosting, and/or Wettability (i.e.,Surface Energy).

1. A coated thermoplastic film comprising: (a) a substrate comprising:(i) a first skin layer having an open-cell voided structure, aclosed-cell voided structure or an uncavitated structure, comprising apolymer, wherein the first skin layer has a first side and a secondside; (ii) an uncavitated core layer comprising a polymer, wherein thecore layer has a first side and a second side, and the first side of thecore layer is adjacent to the second side of the first skin layer; and(b) a first coating on the first side of the first skin layer, the firstcoating comprising at least a first filler component, the first fillercomponent comprising particles having an effective diameter of 5.0 μm to20.0 μm.
 2. The coated film according to claim 1, wherein the first skinlayer has an open-cell voided structure, and the first filler componentcomprises particles having a mean particle diameter satisfying thefollowing equation:D _(mean) =N−T _(skin) wherein D_(mean) is the mean particle diameter(μm) of the first filler component; T_(skin) is the thickness (μm) ofthe first skin layer; and N is in the range of 10.0 μm to 20.0 μm. 3.The coated thermoplastic film according to claim 1, wherein the firstskin layer has a closed-cell voided structure or an uncavitatedstructure, and the first filler component comprises particles having amean diameter in the range of 5.0 μm to 20.0 μm.
 4. The coated filmaccording to claim 1, wherein the first filler component comprisesparticles having a mean diameter in the range of 5.0 μm to 18.0 μm. 5.The coated film according to claim 4, wherein the first filler componentcomprises particles having a mean diameter in the range of 8.0 μm to15.0 μm.
 6. The coated film according to claim 1, wherein the firstcoating further includes a first binder component and a second fillercomponent.
 7. The coated film according to claim 6, wherein a least oneof the second filler component and the first binder component issubstantially hydrophobic.
 8. The film according to claim 1, wherein thefirst skin layer comprises a polypropylene or polyethylene and has adensity of 0.500 g/cm³ to 0.946 g/cm³.
 9. The coated film according toclaim 1, wherein the substrate further comprises: a second skin layercomprising a polymer, wherein the second skin layer has a first side anda second side, the first side of the second skin layer is adjacent tothe second side of the first core layer, and the second side of thesecond skin layer is suitable for a surface treatment selected from thegroup consisting of flame, corona, plasma, metallization, prime coating,printing, and combinations thereof.
 10. The coated film according toclaim 9, further comprising: a second coating comprising at least athird filler component and a second binder component, the second coatingapplied to the second side of the second skin layer, wherein at leastone of the third filler component and the second binder component issubstantially hydrophobic.
 11. The coated film according to claim 1,wherein the first filler component comprises at least one of: a) a claymaterial; b) a natural mineral material; c) a surface-treated naturalmineral; d) a synthetic mineral; e) a surface-treated synthetic mineral;f) plastic particulates; g) thermoplastic particulates, h) silica; i)hydrophilic clays; j) barium sulfate; k) calcium carbonate; 1) titaniumdioxide; m) zinc oxide; n) tin oxide; o) aluminum oxide; p) talc; and q)carbon black.
 12. The coated film according to claim 1, wherein thefirst filler component comprises at least one of: a) a surface-modifiedclay; b) plastic particulates; and c) thermoplastic particulates. 13.The coated film according to claim 1, wherein the first filler componentcomprises a surface-treated polyolefin.
 14. The coated film according toclaim 13, wherein the first filler component comprises surface-treatedpolyethylene.
 15. The coated film according to claim 1, wherein thefirst coating and/or the second coating is applied to the first skinlayer at a weight of from about 0.1 g/m² to about 4.0 g/m².
 16. Thecoated film according to claim 1, wherein the first filler componentcomprises less than 25.0 wt % of the first coating, based on the totalweight of the first coating.
 17. The coated film according to claim 1,wherein the first binder further comprises a crosslinker.
 18. The coatedfilm according to claim 1, wherein the first coating further comprisesat least one of wax emulsions, adhesion promoters, emulsifiers,anti-foams, defoamers, anti-statics, security taggants, co-solvents,wetting aids, and processing aids.
 19. The coated film according toclaim 1, wherein the first skin layer comprises a voiding agent.
 20. Thecoated film according to claim 1, wherein the substrate without thefirst coating has a density of from about 0.30 g/cm³ to about 0.80g/cm³.
 21. The coated film according to claim 1, wherein the firstcoating is in the form of a continuous layer on the first side of thefirst skin layer.
 22. The coated film according to claim 1, wherein thefirst coating is in the form of a pattern or non-continuous layer on thefirst side of the first skin layer.
 23. The coated film according toclaim 1, wherein the first coating layer further comprises a primerlayer in surface contact with the first side of the first skin layer.24. A coated label film for use with a cold glue adhesive, the labelfilm comprising: (a) a substrate comprising: (i) a first skin layercomprising a polymer, wherein the first skin layer has a first side anda second side and is voided with a closed-cell structure; (ii) a corelayer comprising a polymer, wherein the core layer has a first side anda second side, and the first side of the core layer is adjacent to thesecond side of the first skin layer; and (b) a first coating on thefirst side of the first skin layer, the first coating comprising atleast a first filler component, the filler component comprisingpolyethylene homopolymer or copolymer particles having a mean diameterin the range of 5 μm to 20 μm and <2.0 number % of the filler particleshave a diameter >75.0 μm.
 25. A coated thermoplastic film comprising:(a) a polymeric substrate comprising: (i) a first skin layer having aclosed-cell voided or uncavitated structure, comprising a polymer,wherein the first skin layer has a first side and a second side; (ii) auncavitated core layer comprising a polymer, wherein the core layer hasa first side and a second side, and the first side of the core layer isadjacent to the second side of the first skin layer; iii) a second skinlayer having a first side and a second side, wherein the first side isadjacent the second side of the core layer; (b) a first coating on thefirst side of the first skin layer, the first coating comprising apolyethylene filler component, the polyethylene filler componentcomprising particles having a mean diameter in the range of 5 μm to 20μm, a second filler component comprising 30 wt % to 60 wt % of a secondfiller having particle mean diameter of ≦1.0 micron and aself-cross-linking cationic acrylic first binder component; and (c) asecond coating on the second side of the second skin layer, the secondcoating comprising a self-crosslinking cationic acrylic composition.